Medical Neuroscience explores the functional organization and neurophysiology of the human central nervous system, while providing a neurobiological framework for understanding human behavior. In this course, you will discover the organization of the neural systems in the brain and spinal cord that mediate sensation, motivate bodily action, and integrate sensorimotor signals with memory, emotion and related faculties of cognition. The overall goal of this course is to provide the foundation for understanding the impairments of sensation, action and cognition that accompany injury, disease or dysfunction in the central nervous system. The course will build upon knowledge acquired through prior studies of cell and molecular biology, general physiology and human anatomy, as we focus primarily on the central nervous system.
This online course is designed to include all of the core concepts in neurophysiology and clinical neuroanatomy that would be presented in most first-year neuroscience courses in schools of medicine. However, there are some topics (e.g., biological psychiatry) and several learning experiences (e.g., hands-on brain dissection) that we provide in the corresponding course offered in the Duke University School of Medicine on campus that we are not attempting to reproduce in Medical Neuroscience online. Nevertheless, our aim is to faithfully present in scope and rigor a medical school caliber course experience.
This course comprises six units of content organized into 12 weeks, with an additional week for a comprehensive final exam:
- Unit 1 Neuroanatomy (weeks 1-2). This unit covers the surface anatomy of the human brain, its internal structure, and the overall organization of sensory and motor systems in the brainstem and spinal cord.
- Unit 2 Neural signaling (weeks 3-4). This unit addresses the fundamental mechanisms of neuronal excitability, signal generation and propagation, synaptic transmission, post synaptic mechanisms of signal integration, and neural plasticity.
- Unit 3 Sensory systems (weeks 5-7). Here, you will learn the overall organization and function of the sensory systems that contribute to our sense of self relative to the world around us: somatic sensory systems, proprioception, vision, audition, and balance senses.
- Unit 4 Motor systems (weeks 8-9). In this unit, we will examine the organization and function of the brain and spinal mechanisms that govern bodily movement.
- Unit 5 Brain Development (week 10). Next, we turn our attention to the neurobiological mechanisms for building the nervous system in embryonic development and in early postnatal life; we will also consider how the brain changes across the lifespan.
- Unit 6 Cognition (weeks 11-12). The course concludes with a survey of the association systems of the cerebral hemispheres, with an emphasis on cortical networks that integrate perception, memory and emotion in organizing behavior and planning for the future; we will also consider brain systems for maintaining homeostasis and regulating brain state.

De la lección

Neural Signaling: Synaptic Transmission and Synaptic Plasticity

Let’s continue our studies of neural signaling by learning about what happens at synaptic junctions, where the terminal ending of one neuron meets a complementary process of another excitable cell.

Conoce a los instructores

Leonard E. White, Ph.D.

Associate ProfessorDepartment of Neurology, Department of Neurobiology, Duke University School of Medicine; Department of Psychology & Neuroscience, Trinity College of Arts & Sciences; Director of Education, Duke Institute for Brain Sciences; Duke University

[SOUND]

Hello. Welcome to this tutorial on synaptic

transmission. Our core concept is, once again, that

neurons communicate using both electrical and chemical signals.

Now that we've discussed the means for generating electrical signals, we're

ready to talk about how chemical signals are used in neuro transmission.

We have a couple of learning objectives for you today.

first I want you to be able to compare, contrast the structural functional

similarities and differences between electrical and chemical synapses.

I want you to be able to describe, the sequence of events that's responsible for

transmission of neural impulses from one neuron to the next, via a chemical

synapse. I want you to consider that process in

more depth, and characterize the critical role of calcium in chemical

neurotransmission. And lastly, I want you to be able to

discuss the mechanisms of action, by which Botox, which is a compound found in

nature, and now produced for various clinical and cosmetic procedures, how

this compound affects neurotransmission. [SOUND] Let's begin by considering the

general structure and function of electrical and chemical synapses.

Electrical synapses which are illustrated on the left hand side, function by means

of proteins that form channels, called Gap junctions.

And these channels, allow for the passage of small ions that carry current directly

from the cytoplasm of one neuron to another.

Now in contrast, the way chemical synapses work, is via the release of

these packages of neurotransmitter into the synaptic cleft.

These packages are called synaptic vesicles, and the transmitter itself

could be one of a variety of chemical compounds, that has to diffuse across the

gap, between neurons in order to have an effect, on the post synaptic neuron.

Now in order to compare and contrast, the general function and structure of

electrical and chemical synapses, I would invite you to turn to the very end of the

tutorial notes that I've given you, and look at the table, where I've try to lay

out some general properties that allow us to compare and contrast, electrical and

chemical synapses. So, let's begin with some general

functional considerations. Electrical synapses allow for, a very

rapid communication of electrical signals, from one cell to the next.

And this is often very useful. if.

it's important to synchronize a local population of cells, that might be in

contact with one another via these gap junctions.

So here's a slightly more detailed rendering of what a gap junction might

look like. So what we see here are, the close

apposition of two membranes. so much so that it allows for the pairs

of complimentary gap junction proteins, to actually line up in registeration with

one another, from across the two cells that are coming together here.

So these proteins that form these gap junctions, are called connexons.

And they aggregate, to provide an aqueous channel that allows for a current

carrying molecule to pass directly from the cytoplasm of one neuron to another

neuron. So here's another look at what this

might, might look like. So, you can see a variety of connexons

that are all, arrayed. Here allowing for ions to pass from one

location to another, and with it potentially carrying let's say a positive

charge thereby exciting one cell and it's neighbor.

Now, as I mentioned, this mediates very rapid synaptic affects so rapid that this

is the fastest way that neurons have to communicate one with another.

Here in this illustration we see that virtually the same instance that a